Measures of patient safety had a Cronbachs a of
0.79, satisfying the reliability criterion of Nunnally and
Bernstein (1994). The Cronbachs a for measures of
patient safety also had a lower boundary of 0.75,
suggesting that these measures had high reliability
(Iacobucci & Duhachek 2003). This study measured
and used nursing education as a control variable
because Aiken et al. (2003) have identified its potential
influence on patient safety. Notably, nursing education
refers to nurses college, university or high-school edu-
cation, irrespective of accreditation level. Thus, nursing education and accreditation level are not necessarily
correlated. In addition, previous research has found that
time-pressure prevents optimal decision making (Hahn
et al. 1992). Time pressure is intuitively associated with
the number of patients cared for by a single nurse. Thus,
this study included number of patients cared for as a
control variable.